Changes in chemical components of steam-treated betung bamboo strands and their effects on the physical and mechanical properties of bamboo-oriented strand boards

The purpose of this study was to analyze the chemical component change in betung bamboo (Dendrocalamus asper (Schult. & Schult. F.) Backer ex K. Heyne) strands after different steam and washing treatments, and their influence on the physical and mechanical properties of bamboo-oriented strand boards (BOSB). Strands were prepared with three different treatments: (1) steam-only, (2) steam followed by washing with distilled water, and (3) steam followed by washing with 1% sodium hydroxide solution. The steaming process was performed at 126 °C for 1 h at a pressure of 0.14 MPa. Chemical components such as holocellulose, alpha-cellulose, lignin, and starch were analyzed. Phenol formaldehyde resin was used to manufacture BOSB, and the physical and mechanical properties were evaluated in the final products. Steam treatments resulted in changes in chemical components that affected the physical and mechanical properties of BOSB. These changes were mainly caused by the degradation of hemicellulose and extractives dissolved in hot water or 1% sodium hydroxide. These treatments increased the bonding between strands, resulting in higher dimensional stability and strength of BOSB. Considering all the performed experiments, the steam treatment followed by washing with 1% sodium hydroxide was the best treatment for manufacturing BOSB.